Conventionally, as a display device that is worn on a head of a user, a retinal scan display device that directly projects light onto a retina of the user to form an image to cause the user to visually recognize the image is known. For example, a retinal scan display device that includes a control device and a projecting device such that the control device reads identification information from the projecting device, identifies the projecting device based on the read identification information, and specifies an optimum control method is disclosed (for example, see Patent Document 1).